Reconditioning system for moving column of reforming catalyst

ABSTRACT

A system for effecting the reconditioning of catalyst particles used in the reforming of a hydrocarbon stream which provides a vertically elongated confined chamber that will have the particles flow down between screens of perforated plates in a descending column through a carbon burn-off section and a halogenation section. A preferred design provides for an annularform column of particles with gas flows being out-to-in laterally through the column and, in addition, incorporates a drying section in the lower portion of the chamber. An overall system with a preferred design also combines means for scrubbing the flue gas stream from the burn-off section and returning it to the chamber and, in addition, combines means for continuously recycling a steam-halogen-air stream through the halogenation section.

United States Patent Greenwood et a1.

1 51 Mar. 28, 1972 inventors:

Assignee:

Filed:

Appl.

Arthur R. Greenwood, Niles; Kenneth D.

Vesely, Arlington Heights, both of 111.

Universal Oil Products Company, Des

Plaines, 111.

Sept. 25, 1969 U.S. Cl. ..23/288 G, 208/140, 252/415,

References Cited UNITED STATES PATENTS 12/1942 12/1945 l/l950 8/195012/1950 l2/l956 Arveson ..23/288 Hemminger Bergstrom l 0ryingSec/ion+-Ha 2,835,629 5/1958 Berg ..252/418 X 2,856,350 10/1958 Love..208/140 2,934,493 4/ 1960 Borgerson. .208/ 140 3,134,732 5/1964Kearney 208/140 3,243,384 3/1966 Raarup, Jr. ..252/4 1 5 3,375,1903/1968 Mcl-lenry, Jr. et al. ..208/140 X 2,835,560 5/1958 Bason et al...23/288 Primary Examiner-Daniel E. Wyman Assistant Examiner--Paul E.Konopka Attorney-James R. Hoatson, Jr. and Philip T. Liggett 5 7]ABSTRACT A system for efi'ecting the reconditioning of catalystparticles used in the reforming of a hydrocarbon stream which provides avertically elongated confined chamber that will have the particles flowdown between screens of perforated plates in a descending column througha carbon burn-off section and a halogenation section. A preferred designprovides for an annular-form column of particles with gas flows beingout-to-in laterally through the column and, in addition, incorporates adrying section in the lower portion of the chamber. An overall systemwith a preferred design also combines means for scrubbing the flue gasstream from the burn-off section and returning it to the chamber and, inaddition, combines means for continuously recycling a steam-halogen-airstream through the halogenation section.

10 Claims, 5 Drawing Figures Usea Cafa/ysf Recycle F lua Gas HalogenSteam PATENTEDMAR28 ma 3, 652,231

sum 1 [IF 2 Used Gala/ys/ lnle/ Carbon Burn-off Section 7- -Ho/ogenofion0h lor/nofion) Re condition ed Go/o/ysl 55 nvvexv rons:

gig! Arthur R. Greenwood Lift ra 1 Kennel/7 D. Vese/y J' ATTORNEYSRECONDITIONING SYSTEM FOR MOVING COLUMN F REFORMING CATALYST The presentinvention relates to a method and means for effecting the regenerationor reconditioning of used, carbonized catalyst particles. Morespecifically, the present invention is directed to a unitary system foreffecting the multiple stage reconditioning of contacted subdividedparticles of reforming catalyst, with such particles being contacted bythe vaporous and gaseous reconditioning streams as they move in adescending column under controlled gravity flow conditions.

In connection with most hydrocarbon processing operations which arecarried out in the presence of a catalyst, it is quite conventional toprovide means for effecting a periodic regeneration of the catalystparticles; however, in connection with the catalytic reforming of anaphtha or other hydrocarbon charge stream and particularly with aplatinum containing catalyst, most of the process units have operatedwith a fixed bed of catalyst for long periods of time without makingprovision for catalyst regeneration or reconditioning. At such times asreconditioning seemed necessary,'the reactors were shut down and thecatalyst has been entirely removed from each chamber and replaced by newcatalyst or catalyst which was reconditioned at a remote zone.Alternatively, certain plants have been designed with a swing-reactor",i.e., an extra reactor, and in addition, have had elaborate pipingsystems so that one bed at a time could be taken out of service andundergo an in situ regeneration. Neither the complete change of catalystnor the swing-reactor method of regeneration have provided reallysatisfactory systems for maintaining desired catalyst activities andhigh conversions in the multiple reactor bed reforming units and, as aresult, it has been found advantageous to provide for a moving bedcatalytic reforming system and a moving bed regeneration system so thatthere could be an interconnection between the two for, in turn,providing an optimum overall continuously operating plant. It is also ofactual advantage to maintain a continuous operation of a reforming unitso as to have a continuous supply of hydrogen for use in varioushydrogen consuming processing units in the refinery area.

Accordingly, it may be considered a principal object of the presentinvention to provide an improved form of reconditioning system whichmakes use of a gravity flow of catalyst particles down through a seriesof regeneration stages.

It is a further object of the invention to provide an apparatusarrangement which effects contact of the catalyst by lateral flow of thereconditioning streams while the particles are in a descendingannular-form column.

In still another aspect, the invention provides an improved unitaryregeneration chamber which has multiple contact sections and means foraccommodating the high temperature expansion movements of the chamberinternals.

The terms regeneration and reconditioning" are used interchangeably inthe present application and refer to more than one contacting stage orzone, as well as multiple steps of processing. In other words, there ismore than the burn-off of carbon involved in the overall procedure.

Broadly, the present invention provides an apparatus system foreffecting the moving bed regeneration of subdivided particles used inthe reforming of hydrocarbons, which comprises in combination: anelongated vertically positioned confined chamber having an upper carbonburn-off section and a lower halogenation section, said chamber furtherhaving internally positioned spaced apart and vertically orientedperforate screen means thereby providing for a descending column ofparticles therethrough, particle inlet means to the upper end of saidchamber and to the zone between said perforate screen means to providefor a descending column of particles, gas inlet means to said carbonbum-off section and to one side of said screen means and to one face ofsaid column of particles therein and a flue gas outlet means from theopposing side of said screen means and opposing face of the column ofparticles and from said chamber, whereby gas flow is effectedtransversely through said column of particles, a halogen gas inlet meansto said halogenation section and to one side of said screen means forsaid column of particles therein and a residual gas outlet means fromthe opposing side of said screen means and from said chamber, wherebygas flow through such section will be transversely through thedescending column of particles, and catalyst particle withdrawal meansconnects with the lower portion of said chamber and from the lower endof the descending coiumn of particles therein.

In another aspect, the present invention provides a method forcontinuously regenerating contacted carbon containing catalyst particleswithdrawn from a hydrocarbon reforming process zone which comprises: (a)passing the withdrawn particles to the upper portion of a confinedregeneration zone, (b) moving said catalyst through at least a portionof such zone as an elongated moving-bed column, (c) passing an 0,containing stream into contact with the latter to effect a burning andremoval of carbon from said particles, (d) passing the resultingcontacted particles in the continuing moving-bed column to a lowerportion of said regeneration zone and contacting them with a halogencontaining stream to effect halogen addition thereto, (e) subsequentlypassing the halogenated and substantially carbon free particles to adrying zone and contacting them therein with a dry-air stream to effectthe removal of excess adsorbed water or undesired gaseous componentswhile permitting the latter stream to commingle with the halogencontaining stream passing through the particles in the precedingcontacting stage.

It is a particular feature of the present invention, as notedhereinbefore, to provide a unitary system, or more particularly, anelongated chamber which permits a descending column of catalystparticles to move successively through various stages, or sections ofthe chamber, whereby the particles may be successively contacted withthe desired reconditioning streams. In other words, the descendingcolumn will be contacted by a controlled 0;, content carbon removalstream in a first section, contacted by a halogen-steam containingstream in a second and next lower section or stage, and subsequentlycontacted by a hot air stream in a third stage to effect drying. Thecatalyst particles will pass as a continuous column, even though flowmay be periodically stopped and started, and the rate of flow may bemade to be the same through each of the contacting sections althoughcontacting periods may be varied by the cross-sectional area or lengthof the descending column within each section of the elongated chamber.

Although not limiting, the present improved apparatus arrangement isparticularly adapted to carry out the reconditioning of a smallspherical form of reforming catalyst used to convert a naphtha chargestream at conventional reforming conditions. Generally, catalyticreforming of hydrocarbon streams has been effected with the use ofplatinum containing catalysts in fixed bed units and such types ofcatalysts are well known to those skilled in the reforming art.Typically, the platinum-alumina-halogen catalysts, which have been used,or which may be used in the present arrangement, will be in the onethirty-second to one-eighth inch diameter range and preferably of quitespherical form so as to provide a free-flow characteristic that will notreadily bridge or block the descending column system. More specificallyas to type, the catalyst will have platinum composited on alumina in anamount from about 0.1 percent to about 3 percent platinum by weight ofthe alumina. Also, halogen, as fluorine or chlorine, or a combination ofthe two, may be present in an amount from about 0.l percent to 8 percentby weight of the alumina. Chlorine is generally used as the halogen andit is present in an amount from about 0.05 percent to 5 percent byweight of the alumina. In the reforming zone, hydrogen is usuallypresent in a substantial amount which may vary from a mole ratio ofabout l:l to 10:1 and, as a result, carbon formation is rather slow andthe catalyst may be used over relatively long periods of time. However,it is contemplated that the carbon content on the catalyst particlescharged to the present regeneration or reconditioning unit will have onthe order of 2 percent to about 5 percent carbon by weight of thecatalyst.

With respect to the internal design of the elongated verticalregeneration unit, various types of screens or perforate plate means maybe utilized to channel the catalyst particles into a narrow confinedcolumn so that such particles may be contacted in successive stages bygaseous or vaporous treating streams passing laterally therethroughwhile in a descending column. The perforate screen or plate means maycomprise two spaced apart fiat members to form a generally rectangularform descending column of particles but, in a preferred embodiment,there will be utilized two cylindrical form screens with one beingconcentric within the other so that there is a resulting annular-formdescending column of particles. Also, preferably the contacting vaporousor gaseous streams will have out-to-in flows through the bed ofparticles to effect the desired treatment of such particles. In stillanother aspect with respect to the screen construction, each of theparticle confining screens will, in a preferred construction, befabricated in a manner using wire of wedge-shape having across-sectional area decreasing in a direction that is away from theparticle side of the screen. In other words, the particles will flowdownwardly along the face of the screen, in each instance, which has thewide portion of the wedge-shaped wire contacting the particles so thatif any particles, or pieces thereof, do pass through openings betweenwires, they will then flow freely outwardly from the zone of theconfined column of particles into a space having an increasingcross-sectional area.

A preferred reconditioning column design will also be constructed in amanner to provide for the thermal expansion and contraction of theinternal screen members and interior conduit members so as to precludethe possibility of deformation of such members which might occur throughchanging temperature conditions. In other words, a preferred design andarrangement provides for the suspension of the catalyst confining screenmembers from the top portion of the unitary chamber as well as providefor the expansion of any internal conduit means whereby thermalmovements will be accornmodated vertically within the lower portion ofthe elongated chamber. In a secondary aspect, a preferred constructionfurther provides for the assembly and introduction of all of theinternal sections through a removable end portion of the chamber.

In an overall aspect of the present invention which utilizes anelongated vertically oriented unitary chamber which accommodates adescending column of catalyst particles, there may also be providedmeans for introducing the various reconditioning streams into thesuccessive contacting zones as well as means for recycling a majorportion of the contacting streams through the unitary chamber. In otherwords, means is provided for scrubbing the combustion gas stream leavingthe upper carbon burn-off section so as to primarily remove sulfurdioxide, and then returning a major portion of the stream undercontrolled oxygen content conditions to the inlet of the carbon bum-offsection. Also, there may be means provided in combination with thevertical unitary chamber to withdraw the chlorine containing contactingstream from the halogenation section and add steam and additionalchlorine thereto prior to reheating and recycling into the inlet meansprovided for the halogenation section.

Reference to the accompanying drawings and to the following descriptionsthereof will serve to more clearly set forth the present improvedcatalyst reconditioning system as well as describe various advantageousfeatures which will be obtained through the use of such system, and asparticularly adapted for reconditioning a platinum containing reformingcatalyst.

DESCRIPTION OF THE DRAWING FIG. 1 of the drawing is a diagrammatic flowsystem indicating the utilization of a unitary vertically elongatedchamber for accommodating a descending column of catalyst particles.

FIG. 2 is a sectional plan view, as indicated by the line 2-2 in FIG. 1,showing that the descending column of catalyst particles is maintainedas a thin bed between spaced screen members.

FIG. 3 of the drawing is a sectional elevational view of a preferredform of unitary reconditioning chamber where the descending catalyst ismaintained between cylindrical screen members providing an annular-formcolumn.

FIG. 4 of the drawing indicates in an enlarged partial sectional viewthe concentric arrangement of screen members, as shown by the line 4-4in FIG. 3.

FIG. 5 is a partial elevational view indicating particularly the use ofwedge-shaped wire to form the screen members of the unit, as indicatedby the line 5-5 in FIG. 4.

Referring now particularly to FIGS. 1 and 2 of the drawing, there isshown a vertically elongated column 1 adapted to contain a plurality ofcontacting sections for the regeneration of used catalyst particleswhich are introduced into the upper portion of the chamber by way of aninlet 2. In accordance with the present invention, internal screens orperforate plate means such as 3 and 4 are spaced from one another so asto provide a relatively thin descending column of particles 5 which willmove periodically or continuously in a gravity flow manner from the topof the chamber to the outlet end 6. The

burn-off section 7 and a lower halogenation section 8 which is of lessheight than the upper section inasmuch as the contact time periodgenerally will be less than that required in the carbon burn-offsection. There is also indicated below the lower end of the chamber 1,and connecting with outlet end 6, a drying chamber 9 which is adapted toreceive dry air by way of line 10 having controlled valve 11 effectingthe distribution through a perforate ring or other distribution means12. The air and stripped vapors and gases from chamber 9 can pass fromthe upper portion thereof into the lower opening 6 of chamber 1 as wellas through a by-pass line 6 and thence into the particles in thehalogenation section 8, as well as into the burn-ofi section 7.Actually, inasmuch as it is not required to preclude the passage of agaseous stream upwardly from chamber 9, such chamber may, in analternative arrangement be provided directly within the lower portion ofthe elongated chamber 1.

Diagrammatically, there is indicated the recirculation of a flue gasstream into the lower portion of the carbon bum-off section 7 by way ofinlet means I3 such that the gas stream passes laterally below partition15 and through the descending column of particles 5 thence carriesupwardly through the open internal section 14 and laterally back throughthe particles into a collection section 15 which in turn discharges intooutlet 16. The latter discharges into a conduit 17 having valve 17'which connects with a gas scrubber 18 for the removal of sulfur dioxidewhich may be contained in the combustion products stream. The scrubber18 is indicated to be of the venturi-type which receives a recirculatedcaustic stream by way of line 19 and cooler 20 as well as from line 21with valve 22 that in turn receives the fluid from pump means 23 andfrom line 26 connecting to the lower end of a caustic chamber 25. It is,of course, not intended to limit the present regeneration system to theuse of any one scrubber means, since other concurrent and countercurrentscrubbers may well be used. However, in this case, the flue gas streamand caustic from scrubber 18 passes by way of line 24 into the causticseparating chamber 25 whereby separated caustic will flow into outletline 26 and to pump 23 while the resulting scrubbed combustion gasstream will pass through mist extracting means 27 into conduit 28 tocarry to blower means 29 and into conduit 30 having controlled valve 31which efiects the reintroduction of the gases into inlet means 13. Aportion of the combustion gases is shown vented from the system by wayof vent line 32 having control valve 33.

It may also be noted that where low sulfur content feed stocks are beingused and there is not a high sulfur dioxide content in the burn-offgases, then the entire caustic scrubber operation may be eliminated. Inthis event, valve 17' is closed and the gas stream is recycled by way ofline 63 having valve 63 into cooler 20' and thence into conduits 28' and28 to reach blower 29. Also a portion of flue gases may be vented by wayof line 64 with valve 64. i

In the lower halogenation section 8, which is separated from the upperbum-off section 7 by way of partitioning means 34, there is providedmeans for introducing a reconditioning stream such as chlorine alongwith steam and air by way of an inlet means 35. Thus, halogen additionmay also be provided as a step in the system by having lateral flowcontacting of the descending column of particles. Where desired, and asshown by the present embodiment, there is an initial lateral flow belowpartition 38 into zone 36 and then a second lateral flow into a section37 formed above partition plate 38 whereby the resulting unadsorbedhalogen and steam may be discharged by way of outlet means 39. Ofcourse, a certain small portion of the unadsorbed steam and halogen maypass upwardly through the descending column of particles 5 so as to passthe partitioning means 34 and reach the carbon burn-off section 7.

In the preferred system, there is means provided for recycling the steamand halogen stream from outlet 39 by passing such stream into conduit 40connecting with blower means 41 which in turn discharges into conduitmeans 42 connecting with a heater or heat exchange means 43. The latterconnects with and discharges into inlet means 35 for the halogenationsection 8. A charge line 44 with control valve 45 is indicated asproviding means for introducing chlorine and/or other halogen into thesystem by way of line 42, while line 46 with control valve 47 alsoprovides means for introducing additional steam into the reconditioningsystem. The heater 43 may be one which utilizes hot-gases or vapors tobe in heat exchange relationship with the halogen-steam-air stream;however, electrical heating or other suitable forms of heat addition maywell be utilized in the present system.

As a still further step for reconditioning a reforming catalyst prior toits return back to a reforming reactor, it is necessary that there be afinal reduction of the substantially carbon-free, rehalogenatedparticles in the presence of hydrogen or other suitable reducing agentat a high temperature which may be in the range of 600 to 1,200 F. for asuitable reducing time period. The diagrammatic embodiment of FIG. 1provides, in the lower portion thereof, a reducing step as provided bythe commingling of hydrogen with the catalyst particles passage througha heating zone. Where hydrogen is utilized, means is provided to preventits passage into the halogenation zone and the carbon bum-off zone.Thus, as provided by the present improved system, there is movement ofreconditioned particles to the reduction step through a lock-hopper orother equivalent means precluding gas passage from one section toanother. Specifically, there is indicated the passage of dried catalystparticles from the lower portion of chamber 9 by way of outlet means 48to a valving means 49 thence into a lockhopper means 50. The latterpermits periodic discharge of particles therefrom by way of valve 51into a tank means 52. Also, though not shown, there may be a purging ofparticles in the lock-hopper zone. In this instance, the catalystparticles are discharged or withdrawn from the lift tank 52 by use of afluidized lift means utilizing hydrogen introduced by way of inlet line53 and valve 54 to an inner lift pipe 55 extruding upwardly to conduit56 and to a heating-reducing zone 57. The latter is provided with hotgases, vapors or other heating medium by way of inlet line 58 and valve59 so that there is indirect heat exchange relationship with internalconduit means 60 to effect a high temperature reduction of the catalystparticles in the presence of the hydrogen reducing medium. Heat exchangefluid from heater 57 may be discharged by way of line 61 while outletconduit means 62 provides for the discharge of fully reduced andconditioned catalyst for reuse in a reforming reactor.

It should be pointed out that the reducing arrangement illustrated ismerely diagrammatic and other mechanical means for passing a hydrogencatalyst mixture to a suitable heating and reducing zone may be embodiedin the system. For example, a still lower positioned reducing sectionmay be provided directly below the dryer section 9 and the lock-hoppermeans 50 so that there is a gravity flow of catalyst particles and thecontacting of such particles in a lateral flow arrangement or byfluidized contact, with the reducing stream effecting the fluidization.In still another arrangement, the reconditioned but unreduced catalystparticles may be carried to a reforming reactor or at least directlyadjacent the reforming zone where the actual heating and hightemperature reduction is effected by heat supplied from the hydrocarbonvapors being introduced into the reforming reactor. In any case, thereduction step embodies the commingling of hydrogen with the catalystparticles under high temperature reducing conditions for a sufficientlength of time effective to complete the desired reducing step prior tohaving the particles continue into the actual hydrocarbon conversionzone, which period of time is usually at least about 2 hours.

Referring now particularly to FIGS. 3, 4, and 5 of the drawing, there isindicated a preferred method of constructing the elongated chamber foraccommodating a descending column of used catalyst particles throughmultiple reduction-stages. In this preferred construction andarrangement, there is an elongated cylindrical-form chamber 65 havinggas-vapor inlet means indicated at 66 and 67 as well as a removableupper head section 68 whereby certain of the internal sections may beinserted or withdrawn from the interior of the chamber. The largerdiameter or outer cylindrical-form screen member 69 which is inside thechamber 65 has an upper flange 70 that is adapted to be supportedbetween flange portions 71 and 72, which are, respectively, parts of thehead section 68 and the chamber 65. The flange 70 is such as to providefor the suspension of the screen member 69 at a spaced distance from theinside of the wall over chamber 65 and provide a barrier or seal tocause all the inlet gases to pass through the annular bed of catalyst.As internal, smaller diameter screen member 73 is also spaced from 69,while being supported from the top of the removable head section 68, soas to provide an annular space for a descending column of particles 74which communicates with an upper catalyst receiving zone 75, in turnreceiving catalyst particles by way of inlet conduit means such as 76and It will be noted that the respective lower ends of screen members 69and 73 are free to move and expand downwardly under high temperatureconditions and accommodate both expansion and contraction movementswithout causing a buckling of either member. Also, it will be noted thata lower, small diameter wall section 78 for the elongated chamber 65 issized to provide a slip fit at zone 79 with respect to the lower endportion of screen member 69 so that there is a guide means for the lowerend of the latter and a catalyst seal. Also, the lower end portion ofscreen member 73 is provided with suitable guide fins 80 to hold suchmember concentrically within the interior of outer screen member 69.

At the upper end of the chamber, above the removable head section 68,the open end portion of the inner cylindrical screen member 73 connectsto and communicates with an outlet section 81 which, in this instance,is formed as a substantially 90 bend providing a gas outlet port 82.Within the inner screen member 73, there is an elongated axiallypositioned gas outlet conduit 83 which continues on through the wall ofconduit section 81 and discharges into a different or second gas outletportion 84. Preferably, the inner conduit 83 is tapered and provides arelatively large open end section 85 which is adapted to receive gas andvapors from the lower halogenation section of the elongated chamber 65and discharge them to the outlet section 84. A smaller diameter upperportion of conduit 83 permits a gas collection space 86 therearoundwhich increases in cross-sectional area in a downstream directionwhereby the gas stream passing from inlet 66 into annular section 87 andthence through the catalyst bed 74 will be collected in such inner zone86 for discharge by way of outlet means 82.

An intermediate partitioning means in the shape of an annular ring 88 isshown in the space around the external screen member 69 so as to providean upper internal portion for chamber 65 which may be designated as acarbon burn-off end 85 of internal conduit means 83.

ln the lowermost section of the vertical chamber 65, as encompassed bywall section 78, the catalyst particles are collected in a descendingbed 92 from the lower end of the annular column 89 whereby they may bedried prior to being discharged by way of a lower end port 93. A hot anddry air stream, or other suitable drying medium, is introduced into thelower end portion of the drying section 92 by way of a perforatedistributor means 94. The latter connects to and communicates with aninlet port means 95 along a lower side portion of the chamber wallsection 78. Air from bed 92 will pass in part in the column of particles89; however, a major portion will bypass into 90 zone for recirculationthere, as well as pass from the top of halogenation zone 85 to the lowerend of burnoff distribution section 87 so as to supply thereto.

The resulting dried and substantially reconditioned catalyst particlesare withdrawn periodically, or continuously, from the lower end of thechamber 65 by way of the outlet means 93 as has been indicated and maysubsequently be introduced into a suitable reducing zone through arestrictive particle passageway means which will preclude the passage ofa gas or vaporous stream. Such passageway means will normally comprise alock-hopper means and valves or the like, although other means whichwill preclude a back flow of hydrogen may be used. The catalystparticles, as hereinbefore noted, are preferably of a small sphericalnature so that they are free flowing throughout the entire verticalcolumn as well as through the lower moving bed section 92 comprising thedrying section. In order to preclude bridging and to evenly distributeparticle flow, a suitable conical-form particle diverter 96 is showndirectly above the lower outlet means 93.

The size of any slots or openings within the perforate plate or screenmeans 69 and 73 for the present unit will be such as to correlate withthe size of catalyst particles being used in the conversion system. Inother words, where the catalyst particles are of the order ofone-sixteenth inch diameter then the screen openings will be somewhatless in order to preclude any loss of particles through the screenmembers as such particles move by gravity in the descending column asprovided by the present unitary system. Also, a preferred embodiment ofeach of the screen members 69 and 73 provides that each utilizespecifically constructed screen members having wedgeshaped wire. Thistype of screen can be formed by having wire helically wrapped around aplurality of spaced longitudinal members in order to form a continuousopen slot arrangement. The slot will, of course, be of a size topreclude the passage of catalyst particles therethrough.

As best shown in FIGS. 4 and 5, there are indicated in somewhat enlargedviews, the use of inner and outer screen members, respectively 73 and69, which have incorporated the wedge-shaped wire construction. Morespecifically, the inner screen 73 is formed by having a helicallywrapped wedge-shaped wire 97 supported on spaced vertical bars 98 in themanner of a slotted screen construction as generally set forth in US.Pat. No. 2,046,458. With respect to screen 69, it has been refabricatedin manner to have the wedge-shaped wire 99 run vertically over supportbars 100. Preferably, both screens, 69 and 73, would have the wedgewires run vertically so as to minimize attrition of catalyst particlesduring their descending movement. It is to be particularly noted,however, that the wedge-shaped wires 99 and 97 have the wide sideportions thereof positioned inwardly to face and contact the descendingcolumn of catalyst particles. Thus, by this arrangement, the particlesare precluded from lodging within and blocking the space or holesbetween adjacent wires. In the event that any of the particles are ofsmall enough size to pass through a spacing between wedge-shaped wires,then the enlarged cross-sectional area for the slots between wiremembers will permit the particles to pass on through the opening withoutany bridging or blocking effect.

OPERATION OF UNIT ARY RECONDITIONING SYSTEM In order to provide anexample of operation of the improved present form of unitary system, itwill be presumed that the carbon burn-off step will require the catalystparticles to have a contact time of approximately 2 hours while thechlorination or halogenation will require of the order of 1 hour contacttime so that, as a result, the carbon burn-off zone in annular bedsection 74 above partitioning means 88 will be approximately twice theheight of annular bed section 89 which opposes inlet section 90 in turncommunicating with inlet means 67. At the same time, for a dryingsection 92, which will require approximately 2 hours of contact time,then the height of bed portion 92 will be adjusted with respect to itscross-sectional area such that each of the catalyst particles movingtherethrough will require a 2 hour period for completing the descent.

With respect to the lower portion of the column, a heated stream of dryair is introduced by way of inlet means 95 and distributor 94 such thatthe drying will be carried out in the 800 to l,000 F. range. Actually,the quantity of air being introduced is determined by the oxygen demandin the carbon burn-ofi zone which in this instance provides a gas hourlyspace velocity of the order of to 170. This air will, in the presentembodiment, carry on upwardly through the halogenation section intoconduit inlet means 85 for recirculation, although a desired portionwill carry laterally through a top portion of the descending column ofparticles in halogenation section 85 to reach the zone 86 for the airsupply and for recirculation into the carbon burn-off section. Althougha major portion of the air stream will be withdrawn by way of conduit 83and outlet 84 where it will be recycled to the halogenation section inthe manner of FIG. 1, that portion reaching bed section 74 will provideoxygen to the controlled carbon burn-off taking place in this uppersection.

A halogen-steam stream is introduced in inlet means 67 to pass laterallythrough the column portion 89 to provide for adsorption of halogen intothe catalyst particles and to redistribute platinum content to minimumcrystallite sizes in the particles. Any excess steam and halogen willcarry upwardly through the withdrawal conduit 83 to be discharged orrecycled as aforedescribed. For a chlorine containing catalyst, chlorineis added in an amount to maintain of the order of about 2.5 moles perhour in the stream passing into contact with the catalyst at atemperature of the order of 930 F. Steam is admixed with the chlorine atabout 450 F. and at the same time, the volume of the combined gaseousstream will be such as to provide a relatively high gas hourly spacevelocity of the order of 4,700.

In the upper portion of the column where a controlled oxygen contentstream effects the substantial removal or burnoff of carbon which hasbeen deposited on the used catalyst particles, there is a recycledcombustion products stream maintained at a temperature of the order of830 to 930 F., at a gas hourly space velocity which is also of the orderof 4,700. The recycle will be in the manner indicated in FIG. 1 and theoxygen content present for introduction into the carbon burnoff frominlet 66 will be of the order of about 0.7 percent.

It is to be noted that the foregoing example of operation, with thevarious temperatures and quantities set forth, is merely by way ofexample and should not be considered limiting in any way, particularlysince the present improved system may be operated to accommodate anygiven desired temperature ranges within the limits of the materials ofconstruction. Also, the types of reconditioning streams and contactperiods may be varied to suit a particular type of reforming catalystand a particular carbon level or other condition of the catalyst leavingthe hydrocarbon conversion zone. In other words, a carbon level,chlorine level, etc., leaving a particular reforming reactor may varyfrom time to time, or vary with different units accommodating differentcharge stocks with differing sulfur contents etc., so thatreconditioning or regeneration conditions will be varied accordingly.

We claim as our invention:

1. An apparatus system for effecting the moving bed regeneration ofsubdivided catalyst particles used in the reforming of hydrocarbons,which comprises in combination:

an elongated vertically positioned confined chamber having a topportion, an upper carbon burn-off section and lower halogenationsection,

a screen means in said chamber suspended from said top portion of saidchamber and extending downwardly substantially the length of saidchamber and comprising two cylindrical-form screens concentricallydisposed with respect to each other to form an annular catalystretaining section therebetween adapted to accommodate a descendingcolumn of particles therethrough, said screens comprising verticallydisposed, spaced wires,

particle inlet means to the upper end of said chamber and to the zonebetween said perforate screen means to provide for a descending columnof particles,

an upper gas inlet means to said carbon burn-off section and to one sideof said screen means and to one face of said column of particles thereinand a flue gas outlet means from the opposing side of said screen meansand opposing face of the column of particles and from said chamber,whereby gas flow is effected transversely through said column ofparticles,

said flue gas outlet means extending upwardly from the interiorcylindrical form screen means and from the exterior of a residualhalogenation gas outlet conduit, said flue gas outlet means having anenlarged area gas collection section at its upper portion for flue gasflow upwardly around said residual halogenation gas outlet conduit,

a lower halogenation gas inlet means to said halogenation section and toone side of said screen means for said column of particles therein and aresidual halogenation gas outlet means from the opposing side of saidscreen means and from said chamber, whereby gas flow through suchsection will be transversely through the descending column of particles,said residual halogenation gas outlet means being in the form of aconduit axially positioned within the inner of said cylindrical screensand extending through said carbon burn-off section and within said fluegas outlet means, said conduit having a cross-sectional area at itslower end substantially traversing the interior of said inner concentricscreen sand opening into said halogenation zone for collection anddischarge of gases and vapors from said halogenation zone,

a partitioning means between said bum-off and halogenation sections, andcatalyst particle withdrawal means connecting with the lower portion ofsaid chamber and from the lower end of the descending column ofparticles therein.

2. The apparatus as defined in claim 1 wherein said screens comprisewedge-shaped wires with the greater cross sections thereof beinginwardly disposed, (and said wires being mounted vertically with respectto said chamber) whereby to minimize attrition of catalyst particlesduring descending movement thereof through said zones.

3. The apparatus system of claim 1 further characterized in that saidresidual gas outlet means from said chlorination section extendsupwardly through said interior cylindrical form perforate screen meansand from said chamber.

4. The apparatus system of claim 1 further characterized in that each ofsaid perforate screen means is formed of wedgeshaped wire providingresulting wedge-shaped slots therebetween, said outer of the cylindricalscreen means has the wide portion of t he wedge-sl 1a5e d wire along theinner surface thereof and said inner cylm rical screen means has thewider portion of the wedge-shaped wire along the outer surface, wherebyany particle which may pass through spaces between wires of the screenmeans will pass into slots of enlarging cross-sectional area and willnot clog screen openings.

5. The apparatus system of claim 1 further characterized in that acatalyst particle drying section connects with the lower portion of saidchamber below said chlorination section and communicates therewiththrough open passageway means and a drying gas inlet means connects to alower portion of said drying section whereby a drying gas flow will becountercurrently upwardly through the descending particles in saiddrying section.

6. The apparatus system of claim 5 further characterized in that aparticle collection section is provided below said catalyst particledrying section and connects therewith through a gas flow restrictingmeans, a reducing gas inlet means communicates with said particlecollection section whereby such gas is commingled with the particles toprovide a fluidized stream of particles for withdrawal therefrom, aconduit means for the resulting fluidized catalyst particle streamconnects with a particle reducing section, and a heating mediumadditionally connects with the latter for indirect heat exchange withsaid commingled stream whereby there may be a high temperature reductionof such stream.

7. The apparatus system of claim 6 still further characterized in thatsaid particle collection section below said drying section connects withthe latter through a lock-hopper means whereby to preclude gas flowbetween the two sections.

8. The apparatus system of claim 1 further characterized in that theflue gas outlet means from said carbon burn-off section connects with agas scrubber means providing a gas-liquid contact with a caustic liquidto effect the removal of sulfur compounds and conduit means and blowermeans connects with scrubber means with first said gas inlet meansprovides for the resulting scrubbed gas stream return to said carbonburn-off section for lateral flow through the descending particlestherein.

9. The apparatus system of claim 1 further characterized in that the gasoutlet means from said halogenation section connects with arecirculation system including conduit means, a blower means, a heatingmeans, and steam inlet means and halogen addition means, whereby a givenhalogenation level and predetermined temperature level may be providedfor the gaseous charge stream to the halogen gas inlet means to saidhalogenation section.

10. The apparatus as defined in claim 1 wherein said residualhalogenation gas outlet conduit is tapered through said carbon bum-offsection with an increasing cross-sectional area toward the lower endportion, whereby there is an increasing area gas collection section forflue gas flow upwardly around said conduit.

2. The apparatus as defined in claim 1 wherein said screens comprisewedge-shaped wires with the greater cross sections thereof beinginwardly disposed, (and said wires being mounted vertically with respectto said chamber) whereby to minimize attrition of catalyst particlesduring descending movement thereof through said zones.
 3. The apparatussystem of claim 1 further characterized in that said residual gas outletmeans from said chlorination section extends upwardly through saidinterior cylinDrical form perforate screen means and from said chamber.4. The apparatus system of claim 1 further characterized in that each ofsaid perforate screen means is formed of wedge-shaped wire providingresulting wedge-shaped slots therebetween, said outer of the cylindricalscreen means has the wide portion of the wedge-shaped wire along theinner surface thereof and said inner cylindrical screen means has thewider portion of the wedge-shaped wire along the outer surface, wherebyany particle which may pass through spaces between wires of the screenmeans will pass into slots of enlarging cross-sectional area and willnot clog screen openings.
 5. The apparatus system of claim 1 furthercharacterized in that a catalyst particle drying section connects withthe lower portion of said chamber below said chlorination section andcommunicates therewith through open passageway means and a drying gasinlet means connects to a lower portion of said drying section whereby adrying gas flow will be countercurrently upwardly through the descendingparticles in said drying section.
 6. The apparatus system of claim 5further characterized in that a particle collection section is providedbelow said catalyst particle drying section and connects therewiththrough a gas flow restricting means, a reducing gas inlet meanscommunicates with said particle collection section whereby such gas iscommingled with the particles to provide a fluidized stream of particlesfor withdrawal therefrom, a conduit means for the resulting fluidizedcatalyst particle stream connects with a particle reducing section, anda heating medium additionally connects with the latter for indirect heatexchange with said commingled stream whereby there may be a hightemperature reduction of such stream.
 7. The apparatus system of claim 6still further characterized in that said particle collection sectionbelow said drying section connects with the latter through a lock-hoppermeans whereby to preclude gas flow between the two sections.
 8. Theapparatus system of claim 1 further characterized in that the flue gasoutlet means from said carbon burn-off section connects with a gasscrubber means providing a gas-liquid contact with a caustic liquid toeffect the removal of sulfur compounds and conduit means and blowermeans connects with scrubber means with first said gas inlet meansprovides for the resulting scrubbed gas stream return to said carbonburn-off section for lateral flow through the descending particlestherein.
 9. The apparatus system of claim 1 further characterized inthat the gas outlet means from said halogenation section connects with arecirculation system including conduit means, a blower means, a heatingmeans, and steam inlet means and halogen addition means, whereby a givenhalogenation level and predetermined temperature level may be providedfor the gaseous charge stream to the halogen gas inlet means to saidhalogenation section.
 10. The apparatus as defined in claim 1 whereinsaid residual halogenation gas outlet conduit is tapered through saidcarbon burn-off section with an increasing cross-sectional area towardthe lower end portion, whereby there is an increasing area gascollection section for flue gas flow upwardly around said conduit.